The present invention relates to an arrangement for a regulator which works with a thread or yarn supply which is intended to provide a draw-out length of the thread or the yarn which is dependent on the one hand on the size of the supply and on the other hand on an assumed thread tension in the drawn-out thread or the drawn-out yarn.
It is already well-known to use regulators in connection with textile machines of various types, for example for weaving machines. The role of the regulator is, before each drawing-out function or pick in the machine, to accumulate a thread or yarn supply from a thread or yarn magazine, which supply represents the draw-out length. The purpose of the regulator is that, during the drawing-out function, it is intended to provide a constant thread tension in the drawn-out thread, which is to result in high quality of the woven product.
It is also known to arrange regulators so as to be capable of taking up different quantities of thread or yarn so that one and the same regulator can perform weaving functions with different thread lengths, that is to say the regulator can be adjusted so as to be loaded with different quantities of thread or yarn. During weaving in a case in point, the regulator is therefore adjusted so as to be capable of, in its thread or yarn supply, bringing about a draw-out length of the thread/yarn which corresponds to the weaving case concerned. The draw-out length is in this connection related to both the size of the supply and an assumed thread tension (a desired value) with which the system is to work in the weaving or product-manufacturing case in question.
Increasingly high standards are, however, set for the products which are manufactured using the textile/weaving machines in question. In this connection, it has also been found that if attempts are made to fix and maintain the assumed thread or yarn tension by means of the function of the regulator and various arrangements associated with the regulator, the problem exists of accurately fixing the actual thread tension in and during each product-manufacturing case. Various factors can change the thread or yarn tension, for example the functions of shuttles, projectiles, warp threads, patterns etc. This can lead to a certain compensation of the draw-out length, that is to say the size of the supply, taking place by virtue of the draw-out thread being stretched differently during the various thread or yarn traverses. This results in the threads or yarns being tensioned to varying degrees in the woven material, which results in the product failing to meet the desired quality requirements. The invention aims to solve this problem and proposes an adjustment function for the size of the thread or yarn supply during an adjustment stage and/or continuously during manufacturing of the product in the machine in question. In this connection, in each adjustment case, the thread or yarn can be sensed during a pick and regulation of the thread or yarn tension can take place for the next pick etc.
There is also a need to be able to indicate thread or yarn discontinuity in a manner which is technically simple and preferably integrated into the components used. The invention also solves this problem.
There is also a requirement in this context that previously known components can be used and that machines which are already installed and set up can be provided with the new facility without excessive rebuilding. The invention also solves this problem.
An arrangement according to the invention can be considered to be characterized mainly in that a) a load cell is arranged so as to sense the actual thread tension in the drawn-out thread or the drawn-out yarn and to supply to the regulator information for changing the size of the thread or yarn stock when the actual thread tension deviates from the assumed thread tension, and/or b) the load cell supplies pick-monitoring information by means of which the load cell provides information about thread or yarn discontinuity occurring on the thread or the yarn, about whether the gripping function of the projectile or shuttle is operating etc.
In embodiments of the invention, the information for changing the size of the thread or yarn stock brings about a reduction in the diameter of the thread or yarn supply of the regulator so that, in the event of the actual thread tension being lower than an assumed thread tension, the diameter of the thread or yarn supply/the regulator is reduced in order to increase the tension in the thread/the yarn during the next pick. It is also a feature of said embodiments that the information for changing the size of the thread or yarn stock brings about an increase in diameter in the thread supply of the regulator so that, in the event of the actual thread tension being higher than an assumed thread tension, the diameter of the thread or yarn supply/the regulator is increased in order to reduce the tension in the thread/the yarn during the following pick. The regulator receives said size-changing information as soon as the actual thread tension deviates from the assumed thread tension or the latest thread tension read by the load cell. The regulator and the load cell or the load cells can be arranged in a weaving machine for flat-woven wire. A shuttle or projectile is arranged so as to perform the drawing out of the thread from the thread supply of the regulator. The load cell can be arranged at the exit of the regulator for thread or yarn delivery. Each load cell can be connected to the control unit of the machine/weaving machine, which senses the information signal of the load cell and supplies a control signal depending on the sensing to the regulator. The load cell can also provide a thread-monitoring information signal to stop circuits in the machine (and/or, if appropriate, the regulator) in the event of discontinuity occurring in the thread/the yarn.
As a result of the proposals made above, uniform thread or yarn lengths with the same thread tensions are obtained in the various draw-out threads or draw-out yarns in the material manufactured irrespective of the mechanical circumstances or conditions prevailing during manufacture of the material or product, for example the weaving. Load cells well-known per se can be used together with existing regulators, which guarantees reliable and financially advantageous operation. A simple pick-monitoring arrangement can in this connection also be obtained in the machine in question (regulator).